}

  public void testPartition_badSize() {
    Iterable<Integer> source = singleton(1);
    assertThrows(IllegalArgumentException.class, () -> Iterables.partition(source, 0));
  }

  public void testPartition_empty() {
    Iterable<Integer> source = emptySet();
    Iterable<List<Integer>> partitions = Iterables.partition(source, 1);
    assertTrue(Iterables.isEmpty(partitions));
  }